1. Field of the Invention
The present invention relates to an apparatus for assembling a swash plate with pistons in a swash plate compressor. In particular, the apparatus for assembling a swash plate with pistons in a swash plate compressor of the present invention can automatically assemble the swash plate with double or single head pistons and shoes thereby improving workability and productivity.
2. Background of the Related Art
In general, a compressor in a vehicle cooling system selectively receives power from an engine through a vehicle pulley in response to engagement/disengagment of an electronic clutch in order to suck in refrigerant which is heat exchanged in an evaporator, compress the refrigerant with a piston and discharge the compressed refrigerant to a condenser.
Compressors are divided into various forms such as reciprocating and rotary compressors according to their compression policy and structure. Reciprocating compressors are further divided into crank, swash plate and wobble plate compressors. Rotary compressors are further divided into vane rotary and scroll compressors.
In the above various compressors, the swash plate compressor can be generally divided into fixed and variable capacity compressors, in which the fixed capacity compressor uses double head pistons, and the variable capacity compressor uses single head pistons.
Hereinafter the fixed capacity compressor and the variable capacity compressor will be described briefly with reference to FIGS. 1 and 2.
First, as shown in FIG. 1, a fixed capacity compressor includes a front housing 4 having a front cylinder 4a integrally formed within the front housing 4, a rear housing 5 coupled in face-contact with the front housing 4 and having a rear cylinder 5a integrally formed within the rear housing 5, a plurality of double head pistons 6 arranged in a linearly reciprocating fashion in bores 4b of the front cylinder 4a and bores 5b of the rear cylinder 5a, a drive shaft 7 arranged in a rotatable fashion through central portions of the front and rear cylinders 4a and 5a of the front and rear housings 4 and 5, a swash plate 8 mounted at an inclination on the drive shaft 7 so that it is turned in response to rotation of the drive shaft 7 to move the pistons 6 forward and backward and front and rear valve switches 9 arranged respectively between the front cylinder 4a and the front housing 4 and between the rear cylinder 5a and the rear housing 5.
The reference numeral 6a designates a shoe.
Then, as shown in FIG. 2, a variable capacity swash plate compressor includes a cylinder block 10, a front housing 20, a rear housing 30, single head pistons 40, a drive shaft 50, a rotor 60, a swash plate 70, a valve unit 80 and a control valve 90.
The cylinder block 10 has a central bore 11 and a plurality of cylinder bores 12 extended through the cylinder block 10. The cylinder bores 12 are formed radially around the central bore 11 at a uniform interval.
The front and rear housings 20 and 30 are arranged respectively in front and rear ends of the cylinder block 10 so that three components of the front and rear housings 20 and 30 and the cylinder bock 10 are coupled into one part via an elongate bolt 21.
Each of the single head pistons 40 is slidably arranged within each of the cylinder bores 12, and has a body 41 and a bridge portion 42.
The drive shaft 50 is extended rotatably through a central portion of a front wall of the front housing 20 and a crank chamber 22 formed within the front housing 20 so that a rear end of the drive shaft 50 being supported rotatably to a central portion of the cylinder block 10.
The cylinder block 10 together with the front housing 20 defines an internal space, which is in a hermetic state to be used as the crank chamber 20.
The rotor 60 is mounted around the drive shaft 50 in a front portion of the crank chamber 22 to be turned in response to rotation of the drive shaft 50.
The swash plate 70 is installed in a central portion of the crank chamber 22 in such a fashion that it can be adjusted in inclination around the drive shaft 50. In more detail, the swash plate 70 and the rotor 60 are connected via a hinge mechanism to be turned together with the same.
That is, a support arm 61 is projected from a surface portion of the rotor 60 outward along the drive shaft 50, and a swash plate arm 71 is projected from a surface portion of the swash plate 70 toward the support arm 61 of the rotor 60. The support arm 61 is connected with the swash plate arm 71 via a pin 62.
A portion of the outer periphery of the swash plate 70 is rotatably inserted into the bridge portion 42 of the single head piston 40.
As connected with the rotor 60 and the bridge portion 42 of the single head piston 40, the swash plate 70 can be turned not only along with the rotor 60 at rotation by the drive shaft 50 but also forward and backward around the pin 62 in response to the internal pressure of the crank chamber 22 so that the inclination of the swash plate 70 can be adjusted.
In the meantime, the valve unit 80 is arranged between the cylinder block 10 and the rear housing 30 to regulate intake and discharge of refrigerant.
A prior art for assembling the double head piston 6 or the single head piston 40 to the swash plate 8 or 70 as shown in FIGS. 1 and 2 is disclosed in Korean Patent Application Publication No.1999-0064088.
According to the prior art, when the pair of shoes are mounted on notch of the pistons with spherical surfaces of the shoes being laid toward bottoms of the notch, and a slide table loaded with the pistons is moved toward the swash plate, the spherical surfaces of the shoes are vertically rotated through the right and left outside the notch while flat surfaces of the shoes are contacted with both sides of the periphery of the swash plate so that the pistons together with the shoes are mounted on the swash plate. As a result, there is a problem that an additional pressing member is used to ensure a space so that a peripheral portion of the swash plate is inserted between the shoes before the pistons are assembled to the swash plate.
Although the assembling process of the prior art is completed when the spherical surfaces of the shoes are vertically rotated through the right and left outside the notch and at the same time flat surfaces of the shoes are contacted with both sides of the periphery of the swash plate, there is a problem that the shoes are frequently shifted in positions during being pressed by the pressing member and erroneously assembled to the swash plate thereby lowering assembly rate.
Since the prior art tightens center bolts installed in a center stand to fix both ends of a rotational shaft or uses center pins provided in a support head in order to fix the swash plate at a predetermined angle, there is another problem that an apparatus is complicated.
Furthermore, according to the prior art, both heads of the pistons assembled to the swash plate are supported by two piston supports or piston supports of the two support heads. Then, there is also a problem that the apparatus is complicated.